This invention is directed to bird feeders and, more particularly, to a seed delivery system for replenishing a plurality of vertically spaced feeding stations in said bird feeder. While the invention is described with respect to a thistle feeder (for thistle seed), it is also intended for use with more conventional bird feeders with larger feed apertures.
During recent years, there have developed a number of types of bird feeders including many which supply feed apertures from a central supply of feed. Most of such bird feeders provide a central chamber which is filled, and a plurality of apertures in the side wall of said chamber through which birds can gain access to the feed therein.
A first type of bird feeder provides a plurality of apertures in the reservoir which contain the central supply of feed. However, the apertures are all located at or near the bottom of the feeder. Such a design limits the number of feeding apertures possible and, therefore, the number of birds which can feed at any one time.
Later designs have developed in which the bird feeders are provided with vertically, and usually peripherally spaced feeding apertures. One serious drawback with such bird feeders is that, as feed is depleted in the tubular housing, it quickly drops below the level of the upper feeding apertures. As a result, these apertures have no supply of feed and are therefore useless until the entire feed tube is refilled. Thus, the number of effective feeding apertures which may be utilized at any one particular time is limited, and the advantages which would have been offered by the multiple feeding stations is, for the most part, offset.
U.S. Pat. No. 4,201,155 to Hyde, Jr. is one attempt to address the aforedescribed problem. In the Hyde patent, there is provided a means for retaining a supply of feed at vertically spaced feeding stations which is, to some extent, independent of the level of the main supply in the housing. This is accomplished by providing a rectangular housing with a baffle member associated with each feed station. The baffle member retains a supply of feed for each station while allowing the remainder of the supply of feed to pass along to the feed stations thereunder. While the approach of Hyde partially addresses the problem, the problem is not fully solved, because the supply of feed retained at the upper feed stations is considerably less than that available at the lower feed station. Also, the Hyde concept appears to be compatible only with rectangular-shaped housings, while most of the suspended bird feeders today are formed of a cylindrical tube.
Another type feeder which has developed in recent years includes three large tubes which can dispense three different types of seed. Each tube includes an upper and lower chamber and a delivery tube for delivering some of the seed in the upper chamber to the lower chamber. While this approach is also somewhat successful, it is limited to two vertically spaced chambers.